Title: ``BV formalism and homotopy algebras in field theories (review)'' ``QFT calculations via BV Lagrangian's homotopy algebra'' Abstract: A lot of calculations in QFT textbooks can be performed in a homology/homotopy algebraic way by applying the BV formalism to a given field theory. In this talk, we deliver a crush review course of the BV-BRST formalism and homotopy algebras in field theories, explain our procedure for QFT-calculations, and show some examples.